Can the SARS-CoV-2 virus, responsible for COVID-19, be transmitted by tears or by touching the eyes? Are contact lens wearers therefore more at risk? As these questions arise, here’s what you need to know.

A Chinese ophthalmologist was one of the first victims of COVID-19 after being exposed to an asymptomatic patient. That raised the question of the potential presence of the virus in the eye and its possible transmission through tears. Some organizations were quick to issue advisories regarding the potential risk of wearing contact lenses during a pandemic.

However, these positions need to be qualified by the evidence that has since been disseminated. It is now possible to properly advise lens wearers based on the latest scientific advances.

Respect hygiene measures

Let’s establish right away that wearing contact lenses remains safe as long as patients follow the required hygienic measures. This conclusion comes from a literature review published on April 22, based on nearly 200 peer-reviewed articles.

Some of these articles report the ability of the virus to bind to cells on the ocular surface due to the affinity of one or another of its components. However, such binding does not automatically translate into the ability of the virus to generate an eye infection.

In fact, because of the frequent blinking and exchange of tears, the virus is very unlikely to stay on the eye surface long enough to cause problems. The same concern has been expressed about other diseases, such as AIDS or Creutzfeldt-Jakob disease. Traces of these pathogens have been found in the tears of patients but no cases of direct infection or transmission through the ocular surface have ever been documented. It is the same situation with COVID-19.

Rare eye damage

Ocular manifestations caused by COVID-19 are rare. When they do occur, less than one per cent of infected people experience eye irritation in the form of conjunctivitis, a mild inflammation of the white of the eye (conjunctiva). Generally speaking, viruses, and not bacteria, are the main cause of conjunctivitis.

The COVID-19 conjunctivitis can last 10 to 20 days after the first symptoms related to virus appear. Rarely, the cornea is also affected, in which case it is referred to as keratoconjunctivitis. These conditions are well controlled with the usual treatments for these diagnoses, without major long-term complications.

Are contact lenses a vector?

Contact lenses are worn by more than 140 million people worldwide and remain a very effective and safe way to correct vision.

The first element to consider is the lens itself. Can it be a vector for the propagation of the virus?

Although the virus can live on inert surfaces, there are no studies proving that in the ocular environment, the virus can colonize the lens and remain there. Therefore, the lens cannot be seriously considered as a vector for the transmission or spread of the disease. The use of daily disposable (single use) lenses further reduces this possibility. This mode of wear is recognized as the safest in all conditions for eye health.

The second element is lens handling, which involves touching the eyes during insertion and removal of the lens. It is becoming apparent that hand washing, usually recommended during lens wear, is even more critical in a pandemic.

That being said, hands should be thoroughly dried before handling lenses because tap water may be contaminated with pathogens, other than SARS-CoV-2, that are more virulent and damaging to the eye. Never rinse your lenses or the lens case with tap water, let alone store them in it. Hands should be dried with disposable paper, not reusable towels that can easily become contaminated.

Finally, lens care should be performed with products recommended by eye-care professionals and specifically formulated for this purpose. Ideally, a peroxide solution should be used for disinfection and overnight soaking. A saline solution formulated for contact lenses should be used to rinse lenses in the morning prior to insertion.

Glasses are not the solution

For those who hesitant, is it better to consider wearing glasses while waiting for a return to normal? The answer is no. Indeed, it is proven that glasses are often poorly adjusted and that they slip, forcing the person to touch their face more frequently than when wearing lenses, most of the time without being able to wash their hands beforehand. The risk of transmission therefore increases proportionately.

This risk is all the more present since the virus can live for several days on plastic as well as on frames. Contamination by droplets that the person is exposed to and the adhesion of the virus on this surface is more likely than in the case of contact lenses. Finally, the eyewear does not act as a shield against the virus: the nose and mouth remain the doorways for entry. In short, regular corrective glasses should not be considered a personal protective device against COVID-19.

In the rare event that the lens wearer develops abnormal symptoms (redness, pain, sensitivity to light, foreign body sensation, abnormal secretions during or after wearing the lenses) he or she should contact an optometrist or ophthalmologist immediately. A remote (telemedicine) or, if required, in-office consultation can then be arranged quickly.

Some hygiene tips

Although the presence of the SARS-CoV-2 virus has been observed in the tears of some sick patients, it is highly unlikely that this route of transmission leads to the development of systemic disease or localized infection of the eye.

In these circumstances, contact lenses may be considered safe to wear provided that the following hygiene recommendations are strictly followed:

1. Thoroughly clean hands before and after handling contact lenses.

2. Dry hands thoroughly with a clean, disposable cloth.

3. Do not use tap water to rinse, clean or soak the lens, even temporarily.

4. If you can, use disposable soft lenses every day (single use), so that no solutions or cases are needed.

5. If reusable lenses are worn, use only the lens care products recommended by your eye-care professional.

6. Replace the lens case after no more than two months. Clean it daily with a contact lens solution. Do not use water, boil it or put it in the dishwasher.

7. Avoid sleeping with contact lenses.

8. Consult an optometrist or ophthalmologist promptly if any unusual symptoms occur.

   

Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de Montréal

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Image: Reuters